Scientists are increasingly using remote censoring digital cameras, or ‘camera traps’, in order to undertake wildlife studies. They are particularly useful in providing reliable evidence on the presence or absence of a species in an area. They are non-intrusive, particularly when compared to more traditional survey methods such as live trapping, identifying tracks or scats and hair sampling devices. While good survey cameras can be expensive, overall they are often cheaper to use due to their ‘set-and-forget’ nature.
An endangered southern brown bandicoot caught on film.
When strategically placed in the landscape, camera traps can provide researchers with data to investigate if a species occurs at a site, as well as its habitat use, home range size and density of a species within a landscape. They can also aid in building distribution models, observing behaviour and observing rare and cryptic species that would otherwise go undetected.
Read how cane toad researchers are using camera traps to survey fauna on a remote island in the Kimberley, Western Australia.
How Do They Work?
Many camera traps work by detecting heat in motion. This means that if an animal passes by the camera, the sensor detects a change in the temperature as it moves past invisible sensors, and this triggers the camera to take a picture. This means that it usually photographs an animal rather than just taking an image of vegetation blowing around in the wind. Also, the animal doesn’t have to be warm-blooded to trigger the camera, it just has to have a different temperature than the surrounding temperature, so reptiles can also be photographed.
Animals are usually enticed to the camera by means of installing a scent lure or bait placed in front of the camera, often in the form of a nice and stinky meat bait for carnivores, like foxes or feral cats, or a bait mix of rolled oats, peanut butter and sticky syrup for small mammals, such as bandicoots, marsupials and native rats.
Camera traps also take images at night – particularly relevant as many Australian species are nocturnal. The cameras do this by either emitting a white flash similar to everyday cameras, or more commonly by using infrared light to illuminate the subject. Though this is much less obtrusive and usually quicker, it does have the disadvantage of taking only monochrome night images, which can make it harder to determine species by their colour patterns.
This brown goshawk flies dramatically toward the camera trap.
Many survey cameras can also take video, or, depending on how you program them, they can take near-video, ‘flicker-book’ effect footage. You can program them to take images only at night, adjust their sensitivity in order to try to avoid taking images of non-target species, or even set them up as a time lapse camera.
For our surveys, cameras are typically left in the bush for around 21 days, as this provides enough data for our statisticians to be confident in results from their analysis and ecological models. However, cameras can be left in-situ as long as is desired, with the batteries and memory cards periodically replaced. Most cameras traps we use today run on simple rechargeable batteries.
Cameras are usually placed at around knee height, but it really depends on the species being targeted. Some camera traps are permanently fixed to structures, , such as rope bridges high off the ground over highways, in order to monitor their use by the arboreal (tree-dwelling) mammals that they were built for.
What Should You Look out for?
Should you come across a camera trap in your hiking adventures, particularly if you like to walk off-track (as it is unlikely you will see them on walking trails), then by all means have a quick peek, but don’t move them and don’t linger too long, as you may deplete valuable battery life and memory card capacity, as well as leave your scent! Camera traps used for scientific research will usually have a contact telephone number attached to them, should you be interested in finding out more about the research.
Occasionally people do get photographed, either without knowing or purposefully for the fun of pulling silly faces on camera! However, due to their remote and cryptic placement, it is generally very rare to be photographed.
A wedge-tailed eagle feeds on a sambar deer carcass.
Rare Moments Caught on Film
There have been some humorous and fascinating moments caught on camera traps. We have seen people making hand puppets from their socks and imitating wildlife (not recommended!). We have also seen a wallaby examine sunglasses that a researcher accidently left at a camera site, observed all kinds of courtship and display rituals, and have even observed rare and endangered animals copulating on camera!
In one example, we witnessed a bushfire burn the area around our camera, leaving the camera itself unburnt and intact.
Typically, though, we photograph wildlife just going about their daily/nightly business of feeding, hunting and resting.
Innovations in Technology
Camera traps, and how we use them, are evolving all the time. From what essentially started out as a hunter’s tool for detecting quarry, many have now become sophisticated, compact and robust, and suitable for use on much smaller animals.
Many camera trap models are specifically built with wildlife surveys in mind. Technological advances mean that sometimes the images on them can be downloaded remotely, or sent to your phone or tablet. It is even possible to re-program them remotely after you have downloaded the images. Aside from that, image recognition software is now becoming usable to sort images according to species for later analysis, as sorting images and identifying species can sometimes be a lengthy and tricky process, particularly with small mammals.
It is certainly possible for individuals or community groups to set up camera traps for the purposes of monitoring wildlife. Some models are fairly cheap and information is readily available to assist in setting them up.
A large lace monitor inspects the pungent bait that has lured it into the camera trap.
For more details on using camera traps, see:
One consideration of course is to ensure that you consult the land holders of places that you may wish to survey, including state or federal-owned public land. It is also advisable to consider theft; the use of cable locks and camouflage is recommended, though most survey cameras come painted in a camouflage pattern.
Camera traps have been used in important research that has helped increase our understanding of the ecology of many native and introduced species in Australia. For example they helped in detecting long-footed potoroos (Potorous longipes) in areas subjected to timber harvesting, and so assisted in setting up protected areas for them. They have also been used to examine the effects of planned burns on introduced predators and their native prey and the behaviour of wild dogs and foxes around electric exclusion fences on sheep properties. They are currently being used as a tool to map the distribution of the endangered Leadbeater’s possum (Gymnobelideus leadbeateri) to increase protection for Victoria’s faunal state emblem.
If you would like more information on the use of camera traps, or would like to learn about research projects that use camera traps, see the Department of Environment, Land, Water and Planning website.
A superb lyrebird fluffs itself up for the camera.